1. Field of the Invention
The present invention relates to an optical member of a tacky layer additional provision type capable of being peeled without causing any injury of a liquid-crystal cell at the time of mistaken adhesive bonding, or the like, and excellent in durability of an adhesive state so as to be adapted for formation, or the like, of a liquid-crystal display, and a resin type cell substrate therefor.
The present application is based on Japanese Patent Application No. Hei. 10-267464, which is incorporated herein by reference.
2. Description of the Related Art
An optical material such as a polarizing plate, a phase-difference plate, an elliptically polarizing plate formed by lamination thereof, or the like, used in a liquid crystal display (LCD) is a key device for the LCD. A method of adhesively bonding the optical material to a liquid-crystal cell in a state of an optical member in which a tacky layer of an acrylic type adhesive, or the like, is added in advance to the optical material is used for the purposes of preventing the quality from varying, improving efficiency in assembling the LCD, and so on.
In the above description, if alien substances such as contaminations, air bubbles, etc. are mixed in a portion when the optical member is adhesively bonded to the liquid-crystal cell, the portion causes visibility failure. Accordingly, the optical member must be peeled or released from the liquid-crystal cell because of the mistaken adhesive bonding so that the liquid-crystal cell can be recycled. The mistaken adhesive bonding is generally found in examination steps, or the like, in a process following the adhesive bonding of the optical member. Accordingly, the optical member is generally peeled or released from the liquid-crystal cell when at least several hours have passed after the adhesive bonding. In some cases, the optical member may be peeled or released from the liquid-crystal cell when a month or more has passed.
The background-art optical member, however, had a problem that variations in cell gaps and injuries such as damage of a cell substrate, etc. were caused by the flexibility, or the like, of the cell substrate when the optical member was peeled or released from the liquid-crystal cell using a resin substrate as the cell substrate. If the adhesive force is reduced so that good releasability is given, there arises another problem that peeling or rising occurs in the optical member or marks made by foaming are generated in the adhesively bonded interface because of the influence of moisture and heat when the optical member is used practically for the LCD, or the like.